How to Terminate Ethernet Cables | RJ-45 Wiring Scheme The typical RJ-11 connector has six terminals. Usually, only the middle four pins are used. The POTS (Plain Old Telephone Service) residential telephone wiring generally contains two pairs of wires - designed for two separate telephone lines. The center pins (Red and Author: Christina Hansen Data & Telephone wiring standards - WesterNet T-568B Color Code for RJ-45 Plug. There are two wiring standards for these cables, called "T-568A" and T-568B" They differ only in connection sequence, not in use of the various colors. The illustration shown is for T-568B. The pairs designated for 10BaseT Ethernet are Orange and Green. The other two pairs, Brown and Blue,..